1. Field of the Invention
The present invention relates to the field of medical devices and methods, more specifically to devices and methods intended to recannalize body lumens and treat and replace valves in the heart and the vascular system.
Balloon angioplasty is a common medical procedure intended to recannalize stenotic arteries and veins by inserting a balloon catheter through the vascular system. A balloon at the distal end of the catheter is inflated inside a stenosed region in the blood vessel in order to open or “recannalize” the stenosed region and improve blood flow through the vessel.
Aortic valvuloplasty, more commonly referred to as just valvuloplasty, uses a similar balloon inflation protocol to open a stenotic aortic valve, i.e. one that has become stiff and dysfunctional from calcium buildup. The balloon is placed into the aortic valve and inflated in an effort to fracture the calcium build-up and increase the opening size of the valve to improve blood flow from the heart.
Both angioplasty and valvuloplasty suffer from shortcomings. The use of bare balloons for such procedures can require very high inflation pressures which stretch the diseased vessel or valve beyond its elastic limits and which can damage the vessel wall in angioplasty procedures or damage the annulus or tear the valve leaflets in valvuloplasty procedures. Bare balloons can also slip from their intended treatment positions in both angioplasty and valvuloplasty procedures, reducing the effectiveness of the treatments and, in the worst cases, damaging the blood vessel or valve.
To overcome at least some of these problems, the use of balloons carrying cutting blades has been proposed. U.S. Pat. No. 5,320,634 describes the addition of cutting blades to the balloon. The blades can cut the lesions as the balloon is inflated. U.S. Pat. No. 5,616,149 describes a similar method of attaching sharp cutting edges to the balloon. U.S. Patent Publication 2003/0032973 describes a stent-like structure having non-axial grips for securing an angioplasty balloon during inflation. U.S. Pat. No. 6,129,706 describes a balloon catheter having bumps on its outer surface. U.S. Pat. No. 6,394,995 describes a method of reducing the balloon profile to allow crossing of tight lesions. U.S. Patent Publication 2003/0153870 describes a balloon angioplasty catheter having flexible elongate elements that create longitudinal channels in a lesion or stenosis.
As an improvement over balloon catheters having cutting blades, the use of scoring cages and of “quilted” balloons has been proposed. Scoring cage balloons are described in a number of patents and pending application, including U.S. Pat. No. 8,632,559; U.S. Pat. No. 8,080,026: U.S. Pat. No. 7,691,119; and U.S. 2009/0105687. Quilted balloons are described in U.S. 2013/0218181. While highly effective, neither solution is ideal for treating all cases of calcified plaque and other stenotic materials in all patients. In particular, in some instances these cage and balloon designs may not able to generate sufficiently high radial forces to fracture recalcitrant calcified plaque deposits in blood vessels and heart and other valves.
For these reasons, it would be desirable to provide improved or alternative catheters and methods for their use to fracture calcified plaque in blood vessels and valves, particularly in aortic and other heart valves. Moreover, it would be desirable if such balloon structures and methods for their use could provide for improved anchoring of the balloon during dilatation of stenosed vascular regions and valves. Still further, it would be desirable if the balloon and related structures could be adapted for other uses, such as for providing and controlling bypass blood flow, particular in valvuloplasty and prosthetic heart valve replacement procedures and, in some cases, serving as a prosthetic heart valve or a component thereof. At least some of these objectives will be met with the inventions described hereinafter.
2. Description of the Background Art
U.S. Pat. No. 8,632,559; U.S. Pat. No. 8,080,026: U.S. Pat. No. 7,691,119; U.S. Pat. No. 6,394,995; U.S. Pat. No. 6,129,706; U.S. Pat. No. 5,616,149; U.S. Pat. No. 5,320,634; U.S. 2003/0032973; U.S. 2003/0153870; U.S. 20090105687 and U.S. 2013/0218181 have been discussed above. U.S. 2005/0288771 describes a stent for treating bifurcations having a plurality of laterally deployable extensions. U.S. 2009/01822409 describes a stent for treating bifurcations having laterally deployable wings. Other U.S. patents and printed publication of interest include: U.S. Pat. No. 6,454,775; U.S. Pat. No. 6,450,988; U.S. Pat. No. 6,425,882; U.S. Pat. No. 6,355,013; U.S. Pat. No. 6,245,040; U.S. Pat. No. 6,210,392; U.S. Pat. No. 6,190,356; U.S. Pat. No. 6,123,718; U.S. Pat. No. 5,891,090; U.S. Pat. No. 5,797,935; U.S. Pat. No. 5,779,698; U.S. Pat. No. 5,735,816; U.S. Pat. No. 5,624,433; U.S. Pat. No. 5,545,132; U.S. Pat. No. 5,470,314; U.S. Pat. No. 5,221,261; U.S. Pat. No. 5,196,024; U.S. Pat. No. 5,100,423, U.S. Pat. No. 4,998,539; U.S. Pat. No. 4,969,458; and U.S. Pat. No. 4,921,984.